EP0126032A2 - Anordnung zur Identifikation und Unterdrückung von unerwünschten Zweitspur-Echos in Radarsystemen - Google Patents

Anordnung zur Identifikation und Unterdrückung von unerwünschten Zweitspur-Echos in Radarsystemen Download PDF

Info

Publication number
EP0126032A2
EP0126032A2 EP84830065A EP84830065A EP0126032A2 EP 0126032 A2 EP0126032 A2 EP 0126032A2 EP 84830065 A EP84830065 A EP 84830065A EP 84830065 A EP84830065 A EP 84830065A EP 0126032 A2 EP0126032 A2 EP 0126032A2
Authority
EP
European Patent Office
Prior art keywords
output
echoes
integrator
suppression
unwanted
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP84830065A
Other languages
English (en)
French (fr)
Other versions
EP0126032B1 (de
EP0126032A3 (en
Inventor
Gaspare Galati
Ennio Giaccari
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Leonardo SpA
Original Assignee
Selenia Industrie Elettroniche Associate SpA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Selenia Industrie Elettroniche Associate SpA filed Critical Selenia Industrie Elettroniche Associate SpA
Publication of EP0126032A2 publication Critical patent/EP0126032A2/de
Publication of EP0126032A3 publication Critical patent/EP0126032A3/en
Application granted granted Critical
Publication of EP0126032B1 publication Critical patent/EP0126032B1/de
Expired legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/50—Systems of measurement based on relative movement of target
    • G01S13/52—Discriminating between fixed and moving objects or between objects moving at different speeds
    • G01S13/522—Discriminating between fixed and moving objects or between objects moving at different speeds using transmissions of interrupted pulse modulated waves
    • G01S13/524—Discriminating between fixed and moving objects or between objects moving at different speeds using transmissions of interrupted pulse modulated waves based upon the phase or frequency shift resulting from movement of objects, with reference to the transmitted signals, e.g. coherent MTi
    • G01S13/526—Discriminating between fixed and moving objects or between objects moving at different speeds using transmissions of interrupted pulse modulated waves based upon the phase or frequency shift resulting from movement of objects, with reference to the transmitted signals, e.g. coherent MTi performing filtering on the whole spectrum without loss of range information, e.g. using delay line cancellers or comb filters
    • G01S13/528—Discriminating between fixed and moving objects or between objects moving at different speeds using transmissions of interrupted pulse modulated waves based upon the phase or frequency shift resulting from movement of objects, with reference to the transmitted signals, e.g. coherent MTi performing filtering on the whole spectrum without loss of range information, e.g. using delay line cancellers or comb filters with elimination of blind speeds
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/06—Systems determining position data of a target
    • G01S13/08—Systems for measuring distance only
    • G01S13/10—Systems for measuring distance only using transmission of interrupted, pulse modulated waves
    • G01S13/20—Systems for measuring distance only using transmission of interrupted, pulse modulated waves whereby multiple time-around echoes are used or eliminated

Definitions

  • This invention relates to a device for the identification and suppression of unwanted second-time-around echoes for radar systems.
  • the device is concerned with the radar field or more particularly with the field of surveillance radars which furnish a non- ambiguous indication of distance, as in the case with the majority of medium and high power radars, and are provided with a transmitter with power oscillator ⁇ Skolnik: Introduction to Radar Systems. M C Graw Hill N.Y. 2 nd Edition 1980).
  • the cancellation of the echoes of the second time around is performed by a coherent transceiver which renders the MTI filter efficient (Skolnik as above) even with these echoes.
  • the transmitting section of the coherent transceiver is based on a power amplifier tube, which is a klystron in the civil applications to which reference is chiefly made here.
  • the coherence obtained by means of the locking of the coherent oscillator (COHO) remains only during the radar sweep.
  • the preceding technique involves a suitable variation of the radar repetition rate from pulse to pulse and a recognition of the pattern of the clutter of the 2 nd time around.
  • the sequence of echoes of point clutter of the 2 nd time around under conditions of varia tion of the repetition rate (PRF-Staggering) is commonly known as the pattern.
  • PRF-Staggering is commonly known as the pattern.
  • This last technique has, however, one substantial limitation: it does not take into account the correlation of amplitude and is not suitable for the processing of groups of pulses.
  • the subject of the present invention is therefore a device suitable for the identification and subsequent cancellation of unwanted 2 nd t.a. echoes in radar systems by means of correlations in range bins of a known delay (Skolnik 2 n d Edition as above).
  • This device is applicable to surveillance -radars which furnish a non-ambiguous indication of distance (as is the case for the majority of medium and high power radars) and are provided with a power oscillator transmitter such as the magnetron.
  • the principle of operation of the device forming the object of the present invention is based on the recognition of a pair of groups of second t.a. pulses (see Figs. 2 and 3) which are seen by the radar as two groups adjoining in azimuth and separa ted by a distance equal to where C is the velocity of light and T 1 , T 2 are the repetition periods of each group.
  • the groups of pulses are arranged such as to occupy an azimuthal extension equal to half the width of the antenna beam; consequently a target is detected in two groups of pulses.
  • the two above-described groups are "statistically dependent" is so far as they are originated by the same reflecting surface (terrain, rain,aeromobilities).
  • statistically dependent we mean that there is a correlation between the two groups as a result of which, if the signal of one of the two groups is strong it is highly probable that the signal of the other groups is also strong.
  • the analysis of the correlation between the groups is the key for the recognition and elimination of anomalous echoes by suppressing the radar video in the relative group.
  • the principle of operation of the proposed invention is the test of two hypoteses, for each range bin:
  • test of the hypoteses can be made in two successive stages :
  • the device which is the subject of this invention performs a comparison betweer the amplitudes of signal relative to the two groups in question. Whenever the comparison indicates that the percentage difference of this amplitude is less than a cer tain threshold, the groups are identified as correlated due to the presence of 2 nd t.a. signals and the whole operation of comparison is repeated for further antenna rotations in order to make the identification more accurate.
  • N G represents the number of pulses an the groups
  • N R represents the number of range cells (elementary intervals of distance)
  • X the amplitude of the signal after the integration of the group
  • B the enabling signal with the subscript A which indicates "actual” and the subscript P which indicates preceding.
  • a delay equal to N G sweeps and N R elementary intervals of distance (range bins) (5) makes available the signals X A , Xp, B A , and Bp.
  • the last two, B A and Bp, are fed to a coincidence circuit (11) or an AND gate the output of which, integrated over a number of scans (9) and compared (10) with a threshold T 2 , furnishes the indication of presence of unwanted echoes (clutter).
  • the first two, i.e. X A and Xp are fed to an organ which identifies the smaller of them (6) and this is sunsequently multiplied (block 7) by a constant K (which is adjustable and allows the probability of a false alarm and detection to be regulated) and subsequently compared (8) with the larger.
  • the result of the comparison is fed to an integrator (9) which operates on a prefixed number of successive scans and then to a comparator (10) and an AND gate (11).
  • the signal at the output of this AND gate is used to suppress the groups in which a 2 nd t.a. echo has been detected.
  • the subject device utilizes digital techniques which permit an easy reliable and compact construction of the delay elements and logic.
  • it is constituted by three printed circuits each one containing in the order of fifty mi- crologic elements.
  • the device has the advantage of allowing the cancellation of unwan ted 2 nd t.a. elements without any need for the use of a klystron transmitter, which as already stated, presents disadvan tages as compared with the simpler magnetron transmitter.
  • the invention can be used in radars with power oscillator tansmitters and with pulses group processing, for instance that described in the work of E. Cristofalo, G. Galati, "Angular accuracy of an FFT-based radar processor" SELENIA Technical Review, Vol. 7, No. 1, 1980.

Landscapes

  • Engineering & Computer Science (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Radar Systems Or Details Thereof (AREA)
EP84830065A 1983-05-04 1984-03-12 Anordnung zur Identifikation und Unterdrückung von unerwünschten Zweitspur-Echos in Radarsystemen Expired EP0126032B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT4821983 1983-05-04
IT48219/83A IT1197641B (it) 1983-05-04 1983-05-04 Dispositivo per l'identificazione e la soppressione di echi indesiderati di seconda traccia in sistemi radar

Publications (3)

Publication Number Publication Date
EP0126032A2 true EP0126032A2 (de) 1984-11-21
EP0126032A3 EP0126032A3 (en) 1987-05-27
EP0126032B1 EP0126032B1 (de) 1992-11-11

Family

ID=11265309

Family Applications (1)

Application Number Title Priority Date Filing Date
EP84830065A Expired EP0126032B1 (de) 1983-05-04 1984-03-12 Anordnung zur Identifikation und Unterdrückung von unerwünschten Zweitspur-Echos in Radarsystemen

Country Status (4)

Country Link
US (1) US4630052A (de)
EP (1) EP0126032B1 (de)
DE (1) DE3485976D1 (de)
IT (1) IT1197641B (de)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2187605A (en) * 1986-03-07 1987-09-09 Plessey Co Plc Radar systems
WO1988000355A1 (en) * 1986-07-07 1988-01-14 Hughes Aircraft Company Multiple range interval clutter cancellation circuit
EP1571462A1 (de) 2004-03-04 2005-09-07 EADS Deutschland GmbH Verfahren zur Auswertung von Radardaten zum vollautomatischen Erstellen einer Karte gestörter Gebiete
EP2743722A1 (de) * 2012-12-14 2014-06-18 BAE Systems PLC Abschwächen der anomalen Ausbreitungsauswirkungen in einem Radar
WO2014091230A1 (en) * 2012-12-14 2014-06-19 Bae Systems Plc Mitigation of anomalous propagation effects in radar

Families Citing this family (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2170678B (en) * 1985-02-01 1988-10-19 Emi Ltd Receiving circuit
US4973968A (en) * 1986-03-07 1990-11-27 Plessey Overseas Limited Radar system for determining first time around targets from multiple time around targets
US4890113A (en) * 1987-12-09 1989-12-26 Westinghouse Electric Corp. Second time around clutter cancellation system
US5036325A (en) * 1989-10-05 1991-07-30 Hughes Aircraft Company Doppler determination system for MTI radars
DE4104907C1 (de) * 1991-02-18 1992-08-27 Dornier Gmbh, 7990 Friedrichshafen, De
US6137852A (en) * 1997-12-23 2000-10-24 Motorola, Inc Phase detector circuit and method of phase detecting
JP5580621B2 (ja) * 2010-02-23 2014-08-27 古野電気株式会社 エコー信号処理装置、レーダ装置、エコー信号処理方法、およびエコー信号処理プログラム
US10222462B2 (en) 2013-02-27 2019-03-05 Waymo Llc Adaptive algorithms for interrogating the viewable scene of an automotive radar
JP6249805B2 (ja) * 2014-02-05 2017-12-20 三菱電機株式会社 レーダ信号処理装置及びレーダ信号処理方法
EP3835822B1 (de) * 2018-08-06 2022-08-24 Mitsubishi Electric Corporation Signalverarbeitungsvorrichtung und signalverarbeitungsverfahren
CN109765536B (zh) * 2018-10-22 2023-04-21 西北大学 基于辅助通道的fda-mimo降维空时自适应杂波抑制方法及设备
JP6797340B1 (ja) * 2020-03-24 2020-12-09 三菱電機株式会社 信号処理装置、レーダ装置および信号処理方法
CN114415123B (zh) * 2022-04-01 2022-07-19 北京海兰信数据科技股份有限公司 一种基于非相参邻域加权脉冲积累处理方法及系统

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3706990A (en) * 1969-06-19 1972-12-19 Thomson Csf Devices for eliminating fixed-echoes
US3828348A (en) * 1971-10-21 1974-08-06 Hughes Aircraft Co System for minimizing multiple time around echos in a coherent-on-receive-doppler radar
US3855593A (en) * 1972-04-25 1974-12-17 Hollandse Signaalapparaten Bv Pulse radar apparatus
GB1490751A (en) * 1974-01-15 1977-11-02 Ericsson Telefon Ab L M Doppler radar
GB1526689A (en) * 1977-07-26 1978-09-27 Int Standard Electric Corp Digital compensator for transmitter instability in mti radar systems

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3023409A (en) * 1956-03-09 1962-02-27 Westinghouse Electric Corp Pulse doppler radar system
US3312969A (en) * 1965-07-09 1967-04-04 Burroughs Corp Radar video processor and clutter eliminator
US4459592A (en) * 1980-10-31 1984-07-10 Long Maurice W Methods of and circuits for suppressing doppler radar clutter

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3706990A (en) * 1969-06-19 1972-12-19 Thomson Csf Devices for eliminating fixed-echoes
US3828348A (en) * 1971-10-21 1974-08-06 Hughes Aircraft Co System for minimizing multiple time around echos in a coherent-on-receive-doppler radar
US3855593A (en) * 1972-04-25 1974-12-17 Hollandse Signaalapparaten Bv Pulse radar apparatus
GB1490751A (en) * 1974-01-15 1977-11-02 Ericsson Telefon Ab L M Doppler radar
GB1526689A (en) * 1977-07-26 1978-09-27 Int Standard Electric Corp Digital compensator for transmitter instability in mti radar systems

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
INTRODUCTION TO RADAR SYSTEMS, second edition, 1983, pages 119-121, International Student Edition McGraw-Hill, Tokyo, MERILL I. SKOLNIK: "Introduction to Radar Systems" *

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2187605A (en) * 1986-03-07 1987-09-09 Plessey Co Plc Radar systems
EP0283599A1 (de) * 1986-03-07 1988-09-28 Gec-Marconi Limited Radarsystem zur Unterscheidung zwischen Echos mit einfacher Laufzeit und Echos mit mehrfachen Laufzeiten
GB2187605B (en) * 1986-03-07 1990-05-09 Plessey Co Plc Radar system
WO1988000355A1 (en) * 1986-07-07 1988-01-14 Hughes Aircraft Company Multiple range interval clutter cancellation circuit
EP1571462A1 (de) 2004-03-04 2005-09-07 EADS Deutschland GmbH Verfahren zur Auswertung von Radardaten zum vollautomatischen Erstellen einer Karte gestörter Gebiete
US7170443B2 (en) 2004-03-04 2007-01-30 Eads Deutschland Gmbh Method for the evaluation of radar data for fully automatic creation of a map of regions with interference
EP2743722A1 (de) * 2012-12-14 2014-06-18 BAE Systems PLC Abschwächen der anomalen Ausbreitungsauswirkungen in einem Radar
WO2014091230A1 (en) * 2012-12-14 2014-06-19 Bae Systems Plc Mitigation of anomalous propagation effects in radar
US9810773B2 (en) 2012-12-14 2017-11-07 Bae Systems Plc Mitigation of anomalous propagation effects in radar

Also Published As

Publication number Publication date
IT8348219A0 (it) 1983-05-04
EP0126032B1 (de) 1992-11-11
DE3485976D1 (de) 1992-12-17
EP0126032A3 (en) 1987-05-27
IT1197641B (it) 1988-12-06
US4630052A (en) 1986-12-16

Similar Documents

Publication Publication Date Title
EP0126032A2 (de) Anordnung zur Identifikation und Unterdrückung von unerwünschten Zweitspur-Echos in Radarsystemen
US5784026A (en) Radar detection of accelerating airborne targets
US3701149A (en) Frequency averaging controlled false alarm rate (cfar) circuit
US4057800A (en) Multi-PRF signal processor system
US5414428A (en) Radar system with pulse compression and range sidelobe suppression preceding doppler filtering
EP0547686B1 (de) Radargerät mit kohärenter Störechoreferenz
US4654665A (en) Radar system
US4021805A (en) Sidelobe blanking system
US5302955A (en) Apparatus for combining data produced from multiple radars illuminating a common target area
US4488154A (en) Radar processor
US4058809A (en) MTI system and method
GB2032725A (en) Moving target indication radar
US4044352A (en) Signal processor
US4155088A (en) Dual frequency transmission apparatus for frequency-agile radar systems utilizing MTI techniques
US4104633A (en) Extended target-log CFAR processor
US4093948A (en) Target detection in a medium pulse repetition frequency pulse doppler radar
US3725926A (en) Frequency diversified radar system
De Martín et al. Sidelobe mitigation in noise radar using sparse signal processing
NL9401767A (nl) Radarapparaat.
JPH0158467B2 (de)
US3408647A (en) Amti radar system
US3109171A (en) Three-pulse canceller for coherent mti systems
US3134101A (en) Moving target indicator
Griffiths et al. Provision of moving target indication in an independent bistatic radar receiver
NL8102044A (nl) Processor voor een radarstelsel.

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Designated state(s): AT CH DE FR GB LI NL SE

RBV Designated contracting states (corrected)

Designated state(s): DE FR GB NL SE

17P Request for examination filed

Effective date: 19841203

PUAL Search report despatched

Free format text: ORIGINAL CODE: 0009013

AK Designated contracting states

Kind code of ref document: A3

Designated state(s): DE FR GB NL SE

17Q First examination report despatched

Effective date: 19890523

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DE FR GB NL SE

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SE

Effective date: 19921111

Ref country code: NL

Effective date: 19921111

Ref country code: FR

Effective date: 19921111

Ref country code: DE

Effective date: 19921111

REF Corresponds to:

Ref document number: 3485976

Country of ref document: DE

Date of ref document: 19921217

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Effective date: 19930312

EN Fr: translation not filed
NLV1 Nl: lapsed or annulled due to failure to fulfill the requirements of art. 29p and 29m of the patents act
PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 19930312